- Asymmetric Domino Reaction of α,β-Unsaturated Aldehydes and α-Acyl α,β-Unsaturated Cyclic Ketones Catalyzed by Diphenylprolinol Silyl Ether
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An asymmetric domino reaction combining vinylogous Michael reaction, hydration of aldehyde, and oxy-Michael reaction proceeds with α,β-unsaturated aldehydes and α-acyl α,β-unsaturated cyclic ketones in the presence of diphenylprolinol silyl ether to afford tetrahydrochromane derivatives with excellent enantioselectivity. After the domino reaction, addition of Wittig reagent and acid in the same reaction vessel promoted a second domino reaction incorporating retro oxy-Michael reaction, isomerization, and Wittig reaction to afford chiral functionalized cyclic 1,3-diene derivatives with excellent enantioselectivity. Overall, six reaction steps proceed in a one-pot procedure.
- Hayashi, Yujiro,Suga, Yurina,Umekubo, Nariyoshi
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supporting information
(2020/11/18)
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- Novel catalytic system: N-hydroxyphthalimide/hydrotalcite-like compounds catalysing allylic carbonylation of cyclic olefins
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N-hydroxyphthalimide (NHPI) combined with stable and recoverable transition metal-aluminium binary hydrotalcite-like compounds (M-Al HTLcs, M = Cu, Ni, Co) as an unprecedented catalytic system was demonstrated for the allylic carbonylation, as the model reaction, of cyclic olefins with tert-butyl hydroperoxide (TBHP), using isophorone (IP) to ketoisophorone (KIP). The results showed NHPI combined with Cu-Al HTLcs to be an efficient catalytic system and the influences of various reaction conditions of the catalytic reaction were optimised. A maximum IP conversion of 68.0 % with 81.8 % selectivity to KIP was afforded under the optimal reaction conditions. Experiments of repeatability and restorability showed Cu-Al HTLcs to be stable for at least five cycles without noticeable loss of catalytic activity. Expanding substrates could also be efficiently converted to the corresponding ketones under the optimised reaction conditions with appreciable yields. A plausible catalytic reaction mechanism was proposed.
- Zhou, Yin,Tang, Rui-Ren,Song, Dan
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p. 888 - 897
(2017/02/05)
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- An efficient and mild oxidation of α-isophorone to ketoisophorone catalyzed by N-hydroxyphthalimide and copper chloride
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N-hydroxyphthalimide (NHPI) and copper chloride (CuCl2) were first utilized for aerobic oxidation of α-isophorone (α-IP) to ketoisophorone (KIP) and the effects of co-catalysts, temperature, reaction time, solvent, amount of CuCl2 and pressure of oxygen were investigated extensively. NHPI/CuCl2 turned out to be highly efficient to this oxidation with up to 91.3% conversion and 81.0% selectivity under mild conditions. And various hydrocarbons including benzylic compounds, cycloalkene and its derivatives were also oxidized smoothly under optimized conditions. Moreover, the possible reaction mechanism was proposed and verified by FT-IR spectra.
- Chen, Lihua,Tang, Ruiren,Li, Zhongying,Liang, Shan
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experimental part
p. 459 - 463
(2012/05/20)
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- Synthesis of α,β-unsaturated ketones and esters using polymer-supported selenium bromide
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Treatment of the polymer-supported α-phenylseleno ketones and esters prepared from polymer-supported selenium bromide with ketone and ester enolates with hydrogen peroxide afford α,β-unsaturated ketones and esters in good yields and high purities.
- Sheng, Shou-Ri,Liu, Xiao-Ling,Wang, Xing-Cong
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p. 279 - 281
(2007/10/03)
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- Use of a Sacrificial Aluminum Anode in the Acylation of Some Olefins
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The acylation of some alicyclic and aliphatic alkenes by the electrochemical generation of a catalyst using a sacrificial aluminum anode was investigated. Substrates were electrolyzed in a dichloromethane solution of an appropriate electrolyte (tetraalkylammonium salts) in the presence of an acylating agent (acetyl chloride or anhydride). Thus, unsubstituted cycloalkenes, namely cyclohexene and cycloheptene, gave by that reaction conjugated ketones, i.e. the corresponding 1-acetylcycloalkenes, as the only unsaturated carbonyl compounds in moderate-to-good yields. Under the same reaction conditions their 1-methyl derivatives gave mixtures of the corresponding conjugated and β,γ-unsaturated isomeric ketones in which unconjugated compounds predominate. In both cases unsaturated ketones were accompanied by different amounts of side products. Terminal aliphatic alkenes (1-hexene, 1-heptene, and 1-dodecene) afforded only conjugated a ketone with a normal skeleton, but in lower yields. The acylation of cyclohexene was studied in more detail, altering the reaction conditions by changing the reaction temperature, the supporting electrolyte, the acylating agent and the electrochemical cell. Mechanistic considerations were made on the basis of the products distribution and some theoretical calculations being made by the MOPAC program package (version 7.0).
- Vukicevic, Rastko D.,Joksovic, Ljubinka,Konstantinovic, Stanimir,Markovic, Zoran,Mihailovic, Mihailo Lj.
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p. 899 - 904
(2007/10/03)
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- Electrochemical Acylation of Some Cyclic Olefins by Using Aluminium Anode
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The electrochemical acylation of cyclohexene, cycloheptene and their 1-methyl derivatives produces alkyl-cycloalkenyl ketones in good yields.The unsubstituted cycloalkenes give α,β-unsaturated ketones, whereas the 1-substituted derivatives yield mixtures of α,β- and β,γ-unsaturated ketones in which the latter products are predominant.
- Vukicevic, Rastko,Konstantinovic, Stanimir,Joksovic, Ljubinka,Ponticelli, Gustavo,Mihailovic, Mihailo Lj.
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p. 275 - 276
(2007/10/02)
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- REACTIONS INVOLVING SELENIUM METAL AS AN ELECTROPHILE. 2. A GENERAL PROCEDURE FOR THE PREPARATION OF UNSATURATED β-DICARBONYL COMPOUNDS
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A variety of β-dicarbonyl compounds can be converted to the corresponding unsaturated derivatives in high yields.The process involves reaction of the β-dicarbonyl carbanion with Se metal, followed by alkylation with methyl iodide to form the methylseleno derivative and subsequent oxidative elimination.
- Liotta, Dennis,Saindane, Manohar,Barnum, Christopher,Ensley, Harry,Balakrishnan, Pattabiraman
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p. 3043 - 3046
(2007/10/02)
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